Manufacture of artificial threads and the like and apparatus therefor



May 29, 1928. 1,671,878

C. F. TOPHAM MANUFACTURE OF ARTIFICIAL THREADS AND THE LIKE AND APPARATUS THEREFOR Filed July 30, 1927 R J g f llYVE/YTOR CHfl/FLEJ WED TOP/#117 BYH/S flTTOF/YEXS Patented May 29, 1928. I

UNITED STATES PATENT OFFICE,

CHARLES FRED TOPHAM, OI! COVENTRY, ENGLAND, ASSIGNOB T COUBTA'ULDS LIMITED, 01 LONDON, ENGLAND.

MANUFACTURE OI ARTIFICIAL THREADS AND THE LIKE AND APPARATUS THEREFOR.

Application filed July 30, 1927, Serial No. 209,452, and in Great Britain October 11, 1928.

This invention relates to the manufacture of artificial threads and the like, and reapparatus therefor, and is of particular value in the production of artificial threads by 5 projecting a solution of a thread-forming substance in a volatile solvent into a warm atmosphere.

As an example of the process according to this invention, and for the sake of clearness, I will describe the invent-ion as applied to the production of artificial silk from a solution of cellulose acetate in acetone, by projecting such solution into a chamber containing warm air, but the invention is not limited to the use of these particular materials.

When starting to project a solution of cellulose acetate in acetone vertically downwards through a jet containing a number of fine holes into an atmosphere of Warm air, it is found that the solution often does not immediately leave the face of the jet and flow downwards into the warm space, but spreads on the face of the jet, and this is particularly noticeable in thecase of the production of threads of fine denier when the quantity of the solution flowing through each hole of the jet in a given time is relatively small.

It has now been discovered that the starting up of the formation of the thread can be much lution passing through the holes of the jet a sudden considerable increase of pressure,

85 in addition to the pressure exerted by the pump or other means, which normally supplies the solution to the jet., The said increase of pressure may be produced for example by means of an auxiliary plunger moving in a barrel, or alternatively by means ofa flexible diaphragm.

I will describe the invention with reference to the accompanying drawings, but the invention is not restricted thereto.

Figure 1 represents diagrammatically a method of carrying out this invention in which an auxiliary pump comprising a plunger moving in a barrel is used for the purpose of supplying the increased pressure, the figure also indicating the relation and connectioh of the said auxiliary pump with facilitated by applying to the sothe other parts of the apparatus. Figure 2 1llustrates in vertical section, on an enlarged scale, the plunger and the barrel, and Figure 3 illustrates a modification in which the sudden increase ofcpressure is effected by means of a flexible diaphragm.

Referring to Figure 1, a pipe A conveys the spinning solution from the reservoir to 'a pump B and a supply pipe E conveys the spinning solut1on from the pum B which may be for example of the type escribed in either of the specifications of British Letters Patents Nos. 17876/1907 or 196791, or a toothed-wheel pump or any other suitable fornr of pump may be used which sup lies definite quantities of solution in definite periods of time, to a jet-C containing a plurality of fine holes, the said jet 0 bein situated at the top end of the spinningc amber D. The supply pipe E at a point between the pump B and the jet C is rovided path a branch pipe F leading to a arrel G 1n which slides a plunger H, the said plunger H being actuated by a' lever J. It is preferred to place a tap K in the branch pipe F between the supp y pipe E and the arrel G, so as to prevent the spinning solution from being .forced into the barrel except at such times as it may be desired to make use of the plunger and barrel for starting the production When it is desired to start this production of thread, after the pump B has filled both the supply pipe E and the branch pipe F, and also the lower part of the barrel G with the spinning solution, the tap K being open, the lever J is raised slowly, thereby lifting the lunger H, and the face of the jet G is wiped with a cloth moistened with acetone, or other suitable solvent in order to remove any solution from it. The lever J is then pressed down sharply, whereupon the solution is forced throu h the holes of the jet C at a speed consi erably greater than would be t e case were the pump B the only means employed for forcing the solution forward; Owing to this 1ncrease of speed, the solution has not the same tendency to spread over the face of the jet 0, but immediately descends 1n fine of the thread by project- I ing the solution through the jet.

streams into the chamber D, where the acetone. contained in the solution evaporates, leaving the cellulose acetate in the form of filaments, which canbe led out of the chamber in association forming a thread. \Vhen the formation of the thread has thus been successfully started, it is desirable to close the tap K until such time as 1t may again be necessary to start the formation of the threads.

The auxiliary plunger and barrel may be of such construction that the plunger fits the barrel from one end to the other end thereof. In this case, however, any cellulose acetate solution which may leak between the plunger andv the barrel will, on reaching the top end of the said plunger, lose more or less of its acetone by evaporation, and a film or layer of hard cellulose. acetate will thereupon be formed, tending to make the plunger diflicult to move. It is therefore preferred to make the plunger and the barrel of the type as illustrated by Figure 2, in which an annular space L is provided in the in terior of the barrel G, the plunger H also passing through this space, which is filled with or contains acetone or other solvent of cellulose acetate, with the result that if any cellulose acetate solution leaks past the lower end of the barrel G and the plunger H it enters the acetone or other'solvent contained in the said space L and remains in solution there. The acetone may be introduced into and removed from the said space L ,by means of two holes M for example which may be closed by means of screws N or any other suitable or convenient means. Any acetone leaking from the space between the up er endsof the barrel and plunger will on y contain a small proportion of cellulose acetate and will not be suflicient to cause the plunger to stick in the barrel.

, through which the solution to When the acetone in the space has acquired a sufiicient quantity of cellulose acetate it can be removed from the said space L by means of the said holes M and fresh acetone or other suitable solvent introduced in its place.

As already stated, the sudden increase of pressure may alternatively be effected by means of a flexible diaphragm which may be arranged in the supply pipe between the pump and the jet, or in a vessel connected by a branch pipe to the said supply pipe.

In Figure 3, B represents the pump bev spun is forced through the pipe E leading to the jet. 0 is a flexible diaphragm and by imparting a sudden pressure to a handle or knob 'P. the diaphragm and the solution imm'ediately below are forced downwards and the pressure is transmitted along the pipe E to the jet C. It is, of course, undesirable that by the return upward motion of the handle P and the diaphragm O the flow of .formed, I declare that the solution through the holes of the jet should be impeded or hindered means may therefore be provided as for example, a catch, which after the diaphragm has been pressed'downwards, is arranged to hold the handle or knob P securely in that position, until such time as it is desired to start the formation of the thread afresh, when the catch may be released, and the knob P and the diaphragm 0 be allowed to rise, the space below the diaphragm being again filled with spinning solution. Alternatively, the diaphragm may be situated in a vessel, which is separated from the main pipe E by means of a small branch pipe, which branch pipe is furnished with a tap in a manner similar'to that illustrated at K in Figure 1.

While the spinning operation is in progress, it is undesirable that any motion of the said plunger or of the flexible diaphragm should influence the rate of flow of the cellulose acetate solution through the jet, and for this reason, may be inserted between the supply pipe and the barrel in which the plunger moves, or between the supply pipe and the flexible diaphragm, or the tap may be dispensed with and other means be provided for securifig the plunger or the diaphragm in a fixed position.

Having now particularly described and ascertained the nature of my said invention as already explained, a tap,

and in what manner the same is to be perwhat I claim is 1. In the production of artificial threads and the like by projecting a solution of a thread-forming substance in a volatile solvent into an evaporative atmosphere, start pp y s.

ing the formation of the thread by to the solution passing through the holes of the jet, a sudden considerable. increase of pressurein addition to the pressure exerted by the pump or other means which normally supplies the solution to the jet.

2. In apparatus for the production of artificial threads and the like from a solution of a thread-forming substance, a perforated jet, and means for exerting pressure upon the solution to force it throughsaid jet, in combination with auxiliary means adapted to impart a sudden considerable increase of pressure to the solution passing through said jet.

3. In apparatus for the production of artificial threads and the like from the solu tion of a thread-forming substance, a perforated jet, and means for exerting pressure upon the solution to force it through said jet, in combination with. auxiliary means comprising a pump adapted to impart a sudden considerable increase of pressure to the through sai of a thread-forming substance, a jet having a plurality of holes therein, and means for exerting pressure upon the solution to force it through said jet, in combination with an auxiliary pump adapted to impart a sudden increase of gressure to the solution passing jet, said auxiliary pumpcomprisin a plunger and a barrel provided with closab e holes for the introduction of a solvent, substantially as described.

In testimony whereof I have signed my name to this specification.

[CHARLES FRED Term. 

